In a wired or wireless local network such as an ad hoc network or the like, a request packet is transmitted and a reply packet is returned between two relay terminals as node devices in an infrastructure mode or an ad hoc mode. A packet transfer path between two node devices is fixed in the infrastructure mode, whereas a packet transfer path (route) between two node devices is changeable in the ad hoc mode.
With a known method for searching for an optimum route needed for a communication in a local network such as an ad hoc network or the like, a wireless terminal connected to the local network sets a bit error rate and a transfer rate between the wireless terminal and its adjacent wireless terminal, and calculates, based on the bit error rate and the transfer rate, a route weight value for a link between the wireless terminals. A certain wireless terminal issues a route search command based on the route weight value and notifies an adjacent terminal of the route weight value in order to set a route for communicating with another wireless terminal. The adjacent terminal similarly propagates the route search command, and sequentially adds the route weight value at this time. The communication counterpart wireless terminal decides an optimum route based on the route weight value after being added, and returns the route to a starting point side.